scholarly journals Effect of Multi-Walled Carbon Nanotubes on Improving the Toughness of Reactive Powder Concrete

Materials ◽  
2019 ◽  
Vol 12 (16) ◽  
pp. 2625 ◽  
Author(s):  
Jintao Liu ◽  
Hang Jin ◽  
Xin Zhao ◽  
Cheng Wang
Keyword(s):  
Carbon Nanotubes ◽  
Energy Absorption ◽  
Tensile Load ◽  
Microscopic Analysis ◽  
Reactive Powder Concrete ◽  
Aspect Ratios ◽  
Capability Indices ◽  
Multi Walled Carbon Nanotubes ◽  
Reactive Powder ◽  
Walled Carbon Nanotubes

Multi-walled carbon nanotubes (MWCNTs) have great potential to improve the strength and microstructure of traditional cement-based materials. In this research, different aspect ratios of MWCNTs (F-type and L-type) were dispersed into water using surfactants, and then incorporated into reactive powder concrete (RPC) for improving mechanical and microstructure properties. With the addition of 0.025 wt.% F-MWCNTs, the 28 days compressive strength and initial-cracking flexural strength increased by 7.2% and 36%, respectively. Moreover, the first-cracking tensile strengths of the composites containing L-MWCNTs were improved by 16%. Energy absorption capability indices were formulated based on tensile load–displacement curves, and results showed that the energy absorption capabilities of RPC at initial cracking improved as a result of the incorporation of MWCNTs. Furthermore, microscopic analysis indicated that MWCNTs decelerate crack development at the nanoscale and improve the initial-cracking tensile strength of RPC.

Compression Test and Energy Absorption of Polyurethane/Multi Walled Carbon Nanotubes Foam Composites

2015 ◽  
Vol 819 ◽  
pp. 246-250 ◽  
Author(s):  
A.A. Sinar ◽  
Zainuddin Firuz ◽  
M.A. Nur Azni ◽  
A.Z. Nur Hidayah ◽  
Md Akil Hazizan ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Compressive Strength ◽  
Energy Absorption ◽  
Palm Oil ◽  
Strength Properties ◽  
Pu Foam ◽  
Methylene Diphenyl Diisocyanate ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes ◽  
Pu Foams

This paper describes the effect of multi walled carbon nanotubes (MWCNTs) on the properties, especially the strength properties of rigid polyurethane (PU) foams produced from palm oil based polyol (POP) and methylene diphenyl diisocyanate (MDI). The foam composites in the ratio of 1:1.1 (wt. %) mixed at speed 2000 rpm. The addition of MWCNTs into PU foam are varies from 0 wt. % to 3 wt. %. The properties evaluated were compressive strength, density and energy absorption. Compressive strength of PU foam composites with 0.5% of MWCNTs showed the highest value 1.162 MPa of compressive strength compared to other foam composites. It was proved by modeling displacement nodal magnitude using NX Software (version 8.5). The density was increased 15.69 % with addition of 0.5 % MWCNTs into the PU foam. Increasing the amount of MWCNTs in PU foam was found to improve the energy absorption from 22.89 J for pure PU to 24.53 J for foam composites with 3 % MWCNTs.

DYNAMICAL PROPERTIES OF MULTI-WALLED CARBON NANOTUBES BASED ON A NONLOCAL ELASTICITY MODEL

2008 ◽  
Vol 22 (28) ◽  
pp. 4975-4986 ◽  
Author(s):  
Y. YAN ◽  
L. X. ZHANG ◽  
W. Q. WANG ◽  
X. Q. HE ◽  
C. M. WANG
Keyword(s):  
Carbon Nanotubes ◽  
Nonlocal Elasticity ◽  
Nonlocal Elasticity Theory ◽  
Length Scale ◽  
Small Length ◽  
Small Length Scale ◽  
Aspect Ratios ◽  
Multi Walled Carbon Nanotubes ◽  
Double Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

This paper investigates the free vibration of multi-walled carbon nanotubes (MWCNTs) with simply supported ends. Based on the nonlocal elasticity theory which allows the effects of small length scale and the more refined van der Waals (vdW) interaction formulas, the equation of motion is first derived and then solved analytically. The results reveal that the effects of the small length scale are significant for small aspect ratios and high radial vibration modes, and are instead insensitive to the number of layers of MWCNTs and weakly dependent on the wall thickness of MWNTs. This finding means that the effects of small length scale on complicated MWCNTs may be simplified to double-walled carbon nanotubes (DWCNTs) or even single-walled carbon nanotubes (SWCNTs).

Compressive Strength and Microstructure of Multi-Wall Carbon Nanotubes Reinforced Cement Composites

2012 ◽  
Vol 450-451 ◽  
pp. 594-599
Author(s):  
Jin Tao Liu ◽  
Dong Ming Yan ◽  
Shi Lang Xu
Keyword(s):  
Carbon Nanotubes ◽  
Compressive Strength ◽  
Carbon Nanotube ◽  
Microscopic Analysis ◽  
Cement Composites ◽  
Cement Pastes ◽  
Multi Wall Carbon Nanotubes ◽  
Multi Walled Carbon Nanotubes ◽  
Reinforced Cement ◽  
Walled Carbon Nanotubes

Advancement in the study of carbon nanotube has enabled its application in civil engineering as constitutive materials or additives. In this study, the availability of applying multi-walled carbon nanotube to improve the characteristics of cement composites was investigated with experiments on more than 30 specimens. The multi-walled carbon nanotubes (MWCNTs) were effectively dispersed in the water with surfactant, which can keep stable for over 3 months. Specimens with MWCNTs of 0.025%, 0.05% and 0.1% of cement (by weight) were tested with a loading machine and then analyzed with a SEM. It was found that the compressive strength of the samples increased with the increasing MWCNTs, it can improve the 7-day compressive strength by 22% . Microscopic analysis (SEM) revealed that carbon nanotubes were surrounded with hydration products. The bridging and debonding of carbon nanotubes in cement pastes was observed as well.

SMALL SCALE EFFECT ON THE FREE VIBRATION OF MULTI-WALLED CARBON NANOTUBES

2008 ◽  
Vol 22 (28) ◽  
pp. 2769-2777 ◽  
Author(s):  
Y. YAN ◽  
W. Q. WANG ◽  
L. X. ZHANG
Keyword(s):  
Carbon Nanotubes ◽  
Free Vibration ◽  
Scale Effect ◽  
Large Scale ◽  
Small Scale ◽  
Beam Model ◽  
Aspect Ratios ◽  
Small Scale Effect ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

This paper is concerned with the free vibration of multi-walled carbon nanotubes (MWCNTs) with simply supported ends. Based on the non-local elasticity theory, Timoshenko beam model with the small scale effect and the van der Waals (vdW) interaction is derived and then solved analytically. The results reveal that the small scale effect is quite significant for small aspect ratios, large scale parameters and high radial vibration modes, whereas it is insensitive to the number of layers of MWCNTs and is weakly-dependent on the wall thickness of MWCNTs.

Diameter-Modulated Multi-Walled Carbon Nanotubes Without Bamboo-Like Partitions: Growth, Structure and Deformation Behaviors

2020 ◽  
Vol 20 (5) ◽  
pp. 3038-3041 ◽  
Author(s):  
Tetsushi Hayashi ◽  
Hideo Kohno
Keyword(s):  
Carbon Nanotubes ◽  
Tensile Load ◽  
Stick Slip ◽  
Catalyst Nanoparticles ◽  
Deformation Behaviors ◽  
Multi Walled Carbon Nanotubes ◽  
Stick Slip Motion ◽  
Walled Carbon Nanotubes ◽  
Periodic Changes

Periodically diameter-modulated stack-type-multi-walled carbon nanotubes are grown from Fe–Ga catalyst nanoparticles using palmitic acid as a carbon source. A model for their formation mechanism is proposed: stick-slip motion of a catalyst nanoparticle in the growing nanotube results in periodic changes of diameter and wall thickness, and formation of inner partitions is suppressed when the degree of supersaturation is low. In addition, behaviors of nanotubes in Joule heating, bending, and under a tensile load were observed in-situ by scanning electron microscopy using micro-manipurators.

Short-Time Effect of Multi-Walled Carbon Nanotubes on Some Histological and Biochemical Parameters in Marine Bivalves Crenomytilus grayanus (Dunker, 1853) and Swiftopecten swifti (Bernardi, 1858)

2017 ◽  
Vol 13 ◽  
pp. 225-231 ◽  
Author(s):  
Anna A. Anisimova ◽  
Olga N. Lukyanova ◽  
Vladimir V. Chaika ◽  
Alexandra A. Kalitnik ◽  
Svetlana A. Danilenko ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Reduced Glutathione ◽  
Microscopic Analysis ◽  
Average Cell Size ◽  
Average Cell ◽  
Total Hemocyte Count ◽  
Marine Bivalves ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

The marine bivalves, mussels Crenomytilus grayanus (Dunker, 1853) and scallops Swiftopecten swifti (Bernardi, 1858), were in vivo exposed to 12-14 nm multi-walled carbon nanotubes (MWNTs) for up to 48 h. Microscopic analysis in combination with the RAMAN spectrophotometry revealed the MWNT aggregates on the gills surface and inside the gut of all exposed individuals. After 48 h exposure, there were no changes in the total cell count, the average cell size and granularity in the hemolymph of mussels, while in the scallops the total hemocyte count was significantly reduced, and the average hemocyte granularity increased. Biochemical markers of oxidative stress (activity of glutathione-S-transferase and catalase, concentration of reduced glutathione, and the degree of lipid peroxidation) did not change significantly in the digestive gland of both mussels and scallops. In hemolymph, catalase activity increased as compared to control in both mussels and scallops. Moreover, concentration of reduced glutathione increased in hemolymph of scallops on the second day of exposure to MWNTs. The data obtained indicate that MWNTs may affect different bivalve mollusks more or less strongly under the same exposure conditions.

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